Conventionally, in an image forming apparatus such as a printer, a copying machine, a facsimile or a multifunction machine, for example, in a printer, an image forming unit, an LED head, a transfer roller, a fixing unit, a sheet sheet cassette and the like are provided. In the image forming unit, a photoreceptor drum, a charging roller, a developing roller, a developer blade, a toner supply roller, a cleaning blade, a toner cartridge and the like are arranged.
In the image forming unit, a surface of the photoreceptor drum that is uniformly charged by the charging roller is exposed by the LED head and an electrostatic latent image is formed. Further, a toner that is supplied from the toner cartridge to a body of the image forming unit, that is, to an image forming unit body, is supplied to the developing roller by the toner supply roller, and the toner on the developing roller is caused to form a thin layer by the developer blade. Next, the toner on the developing roller is attached to the electrostatic latent image on the photoreceptor drum, and the electrostatic latent image is developed and a toner image is formed on the photoreceptor drum.
A sheet as a print medium brought out from the sheet cassette is sent to a transfer part formed between the photoreceptor drum and the transfer roller. After a toner image is transferred by the transfer roller at the transfer part, the sheet is sent to the fixing unit. At the fixing unit, the toner image is fixed onto the sheet and an image is formed on the paper.
However, a printer is provided that includes a duplex printing unit as a standard equipment so that duplex printing can be performed by forming images on both sides of a paper.
In the printer of this kind, a medium carrying device for carrying the sheet is provided with a reversing part, at a position above the sheet cassette and in a vicinity of the fixing unit, for reversing the paper, and a reversed medium carrying part, at a position above the sheet cassette and on a side opposite to the fixing unit, for sending the reversed sheet again to the transfer part (for example, see Japanese Patent Laid-Open Publication No. 2010-222085).
However, in the conventional printer, operability for insertion and removal of a medium guide unit is not high.
A purpose of specific examples described in the present invention is to improve the operability for insertion and removal of the medium guide unit.